Parameter estimation to study the immediate impact of aortic cross-clamping using reduced order models

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Surgical Simulation

Background:

• Aortic cross-clamping is a standard surgical technique.
• Its immediate hemodynamic effects are not well understood.
• Accurate hemodynamic modeling is crucial for patient safety.

Purpose of the Study:

• To develop and validate numerical models for estimating the instantaneous hemodynamic impact of aortic cross-clamping.
• To quantify changes in vascular properties like resistance and compliance.
• To assess the accuracy of these models against real-time surgical data.

Main Methods:

• Developed a zero-dimensional (0D) Windkessel model coupled with parameter estimation.
• Created a one-dimensional (1D) blood flow model of a nine-artery network.
• Recorded invasive pressure signals during abdominal aneurysm repair surgery.
• Validated models by comparing predictions with intraoperative pressure data.

Main Results:

• The 0D model showed a 10% increase in total vascular resistance and a 20% decrease in total compliance post-clamping.
• The 1D model accurately reproduced pressure waveform changes using patient-specific parameters.
• Both models demonstrated high correlation (R² > 0.95) with experimental blood pressure data.

Conclusions:

• Numerical modeling effectively captures the immediate hemodynamic consequences of aortic cross-clamping.
• Patient-specific vascular resistance and compliance are key determinants of pressure waveform changes.
• These models offer a valuable tool for understanding and predicting surgical hemodynamic impacts.